Angioplasty balloon compliance: Can in vivo size be predicted from in vitro pressure profile measurements?

Background and hypothesis: This study was undertaken to determine whether the behavior of angioplasty balloons within coronary arteries may differ from that anticipated from data provided by the manufacturers. In particular, the in vitro pressure-diameter profiles may not truly represent in vivo sizes. Methods: Thus, we assessed the degree of correlation of in vitro with in vivo measurements obtained during routine angioplasty practice. In vivo size of 2.5 mm compliant (n = 8) and 3 mm semicompliant (n = 8) balloons was assessed using quantitative angiography for first, second, and third inflations Results: In vivo size was less than expected from in vitro measurements. In general balloon diameter increased with inflation pressures up to 8 atmospheres, and some degree of elastic recoil was evident with both balloon types after the last inflation. Conclusion: In vivo balloon size may not be accurately predicted from manufacturers' published data. Size is more likely to be affected by factors such as lesion characteristics and elasticity of the vessel wall than by balloon material compliance characteristics.